Flash tank eliminator

ABSTRACT

A flash tank for use in a vapor compression system includes a flash tank housing, an inlet, a vapor outlet, a liquid outlet, and an eliminator. The eliminator is fluidically positioned between the inlet and the vapor outlet. The eliminator includes either a plurality of blades or a piccolo tube connected to the vapor outlet.

BACKGROUND

The present invention relates to vapor compression systems, and in particular, to a flash tank for use in a vapor compression system.

Vapor compression systems commonly compress and expand a refrigerant for use in refrigeration applications. Some vapor compression systems make use of a flash tank. As liquid refrigerant passes through an orifice or valve into a relatively low pressure flash tank, the liquid refrigerant flashes into a combination of liquid and gaseous or vapor refrigerant. Some flash tanks have both a liquid outlet and a vapor outlet. It can be undesirable to flow refrigerant in the wrong phase through the wrong outlet. For example, flowing liquid refrigerant through the vapor outlet can increase power consumption and reduce cooling performance of the vapor compression system.

SUMMARY

According to the present invention, a flash tank for use in a vapor compression system includes a flash tank housing, an inlet, a vapor outlet, a liquid outlet, and an eliminator. The eliminator is fluidically positioned between the inlet and the vapor outlet. The eliminator includes either a plurality of blades or a piccolo tube connected to the vapor outlet.

Another embodiment of the present invention is a method for operating a vapor compression system. The method includes flowing refrigerant from a condenser to a flash tank, separating liquid refrigerant from vapor refrigerant via an eliminator that includes a plurality of blades, flowing vapor refrigerant from the eliminator through a vapor outlet to a compressor, and flowing liquid refrigerant from the eliminator, through a liquid outlet, to an evaporator.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a supplemental cooling unit (SCU).

FIG. 2A is a side schematic view of one embodiment of a flash tank for use in the SCU of FIG. 1.

FIG. 2B is a top sectional view taken along line 2B-2B of FIG. 2A.

FIG. 3A is a side schematic view of another embodiment of a flash tank for use in the SCU of FIG. 1.

FIG. 3B is a top sectional view taken along line 3B-3B of FIG. 3A.

FIG. 4A is a side schematic view of another embodiment of a flash tank for use in the SCU of FIG. 1.

FIG. 4B is a top sectional view taken along line 4B-4B of FIG. 4A.

FIG. 5A is a side view of one embodiment of an eliminator for use in the flash tank of FIGS. 2A and 2B.

FIG. 5B is a top view of the eliminator of FIG. 5A.

FIG. 6A is a side view of another embodiment of an eliminator for use in the flash tank of FIGS. 2A and 2B.

FIG. 6B is a top view of the eliminator of FIG. 6A.

FIG. 7 is a side view of an alternative embodiment of an eliminator.

DETAILED DESCRIPTION

FIG. 1 is a schematic view of supplemental cooling unit (SCU) 10. SCU 10 is a vapor compression system that includes flash tank 12, evaporator 14, compressor 16, and condenser 18, all connected by refrigerant loop 20. Refrigerant loop 20 includes passages 20A-20F. Motor 22 drives compressor 16 to compress vapor refrigerant to a superheated vapor refrigerant. Compressor 16 can be virtually any suitable compressor, such as a scroll compressor or a centrifugal compressor. In the illustrated embodiment, compressor 16 is a variable speed scroll compressor controlled according to inputs received from temperature sensor 24 and pressure sensors 26 and 28. Compressor 16 can also be controlled according to coolant temperature sensed at an outlet of evaporator 14 and a coolant temperature setpoint. Condenser 18 receives a flow of superheated vapor refrigerant from compressor 16, removes the superheat, condenses vapor to a liquid, and supplies a flow of subcooled liquid refrigerant along passage 20D to flash tank 12. As refrigerant flows into flash tank 12, it passes through flash tank orifice 30 where it is flashed and expanded into a combination of liquid and gas.

Liquid refrigerant in flash tank 12 flows through passage 20A to evaporator 14, where the refrigerant is heated and evaporated into a vapor. The vapor refrigerant then flows from evaporator 14 through passage 20B to compressor 16 for the cycle to be repeated. In the illustrated embodiment, thermal expansion valve (TXV) 32 is positioned along passage 20A. TXV 32 is controlled according to inputs received from temperature sensor 34 and pressure sensor 36. Suction pressure regulation valve 38 is positioned along passage 20B. Suction pressure regulation valve 38 can be substantially adjacent to an inlet to compressor 16 and can be part of a common assembly with compressor 16. TXV 32 and suction pressure regulation valve 38 are actuated to control the pressure and temperature of refrigerant leaving evaporator 14 and entering compressor 16. In an alternative embodiment, TXV 32 can be replaced with an electronic expansion valve (EXV), and suction pressure regulation valve 38 can be omitted.

Vapor refrigerant in flash tank 12 flows through passage 20F to economizer port 40 of compressor 16. Flash tank pressurization valve 42 is positioned along passage 20F to control pressure in flash tank 12. Thus, compressor 16 is connected to and receives a flow of vapor refrigerant both from flash tank 12 and from evaporator 14.

Quench trap 44 is positioned along passage 20D between condenser 18 and flash tank 12. Compressor over-temp valve 46 is positioned along passage 20E, which connects passage 20D to passage 20F. When temperature of compressor 16 is sensed to exceed a threshold, compressor over-temp valve 46 can be actuated to supply cooled liquid refrigerant from quench trap 44, through passages 20E and 20F, and to economizer port 40 of compressor 16 to cool compressor 16. During normal operation, compressor over-temp valve 46 can remain substantially closed.

Condenser 18 is a heat exchanger connected to coolant loop 48, which is connected to power electronics cooling system (PECS) 50 of an aircraft (not shown). This allows PECS 50 to cool the refrigerant in condenser 18 of SCU 10.

Evaporator 14 is a heat exchanger connected to coolant loop 52, which is connected to integrated cooling system (ICS) 54 of the aircraft. Integrated cooling system 54 includes one or more aircraft systems that require cooling, such as a galley refrigeration system and a cabin air temperature control system. This allows SCU 12 to cool coolant of ICS 54 in evaporator 14.

FIG. 2A is a side schematic view of one embodiment of flash tank 12 for use in SCU 10 (shown in FIG. 1). Flash tank 12 includes flash tank housing 56 (including top 58 and bottom 60), inlet 62, vapor outlet 64, liquid outlet 66, piccolo tube 68, and eliminator 70. Inlet 62 and vapor outlet 64 are positioned at top 58 of flash tank housing 56. Liquid outlet 66 is positioned at bottom 60 of flash tank housing 56. Piccolo tube 68 has a plurality of holes 72 and is connected to inlet 62. Eliminator 70 has a plurality of blades 74 extending between top support 76 and bottom support 78. Inlet 62 and liquid outlet 66 are positioned on a first side of eliminator 70 while vapor outlet 64 is positioned on a second, opposite side of eliminator 70. In operation, refrigerant from condenser 18 (shown in FIG. 1) passes through inlet 62, into piccolo tube 68, and out holes 72 into flash tank 12 whereby the refrigerant flashes into a combination of liquid and vapor refrigerant. Liquid refrigerant settles toward bottom 60 and flows out liquid outlet 66 to be delivered to evaporator 14 (shown in FIG. 1). Vapor refrigerant rises toward top 58, flows through eliminator 70 and exits out vapor outlet 64 to be delivered to compressor 16 (shown in FIG. 1).

Droplets or a mist of liquid refrigerant can be entrained in the vapor refrigerant flowing through eliminator 70. Eliminator 70 separates the liquid refrigerant from the vapor refrigerant by collecting the droplets of liquid refrigerant, which adheres to blades 74. The liquid refrigerant that adheres to blades 74 then flows down blades 74 toward bottom support 78, and then drips from bottom support 78 to collect at bottom 60 of flash tank 12. Vapor refrigerant flows through vapor outlet 64.

FIG. 2B is a top sectional view of flash tank 12 taken along line 2B-2B of FIG. 2A. FIG. 2B illustrates an embodiment of eliminator 70 where blades 74 are arranged in a single linear row.

FIG. 3A is a side schematic view of flash tank 112, which is an alternative embodiment of flash tank 12 (shown in FIGS. 2A and 2B). Flash tank 112 has eliminator 170. FIG. 3B is a top sectional view of flash tank 112 taken along line 3B-3B of FIG. 3A. Eliminator 170 is substantially similar to eliminator 70 (shown in FIGS. 2A and 2B), except that eliminator 170 includes a plurality of blades 174 arranged in first linear row 174A, which is perpendicularly angled with respect to second linear row 174B, which is perpendicularly angled with respect to third linear row 174C.

FIG. 4A is a side schematic view of flash tank 212, which is an alternative embodiment of flash tank 12 (shown in FIGS. 2A and 2B). Flash tank 212 has eliminator 270. FIG. 4B is a top sectional view of flash tank 212 taken along line 4B-4B of FIG. 4A. Eliminator 270 is substantially similar to eliminator 70 (shown in FIGS. 2A and 2B), except that eliminator 270 includes plurality of blades 274 arranged in first linear row 274A, which is perpendicularly angled with respect to second linear row 274B.

In further alternative embodiments, eliminators 70, 170, and 270 can have blades 74, 174, and 274 arranged in alternative shapes, such as an arc.

FIG. 5A is a side view of one embodiment of eliminator 70 for use in flash tank 12 (shown in FIGS. 2A and 2B). Blades 74 are substantially parallel with one-another and are substantially vertically aligned between top support 76 and bottom support 78.

FIG. 5B is a top view of eliminator 70 of FIG. 5A. FIG. 5B shows that the plurality of blades 74 are arranged in a single linear row and have a plurality of flow paths between blades 74. For example, flow path 80 is defined between blade 82 and blade 84. Blade 82 has bend 86, as do blade 84 and all of blades 74. Bend 86 in blades 82 and 84 cause flow path 80 to have turn 88. Blades 74 are bent enough and spaced close enough such that there is no straight line flow path from inlet 62 (shown in FIG. 2A) to vapor outlet 64 (shown in FIG. 2A). Liquid refrigerant has a greater momentum than vapor refrigerant. Because turn 88 causes an abrupt momentum change along flow path 80, liquid refrigerant flowing along flow path 80 will hit blade 84 and adhere to blade 84 due to surface tension. Vapor refrigerant, on the other hand, will change directions and continue to flow along flow path 80 through blades 74 and eventually flow out vapor outlet 64.

FIG. 6A is a side view of eliminator 370, which is an alternative embodiment of eliminator 70 (shown in FIGS. 5A and 5B). FIG. 6B is a top view of eliminator 370 of FIG. 6A. Eliminator 370 is substantially similar to eliminator 70, except blades 374 have multiple bends, such as bends 386A and 386B in blade 382. Bends 386A and 386B cause flow path 380 to have at least two turns 388A and 388B.

FIG. 7 is a side view of eliminator 470, which is alternative embodiment of eliminator 70 (shown in FIGS. 2A, 2B, 5A, and 5B). In the embodiment illustrated in FIG. 7, eliminator 470 is a piccolo tube with holes 90 and is rigidly connected to fitting 92. Piccolo tube 68 is also rigidly connected to fitting 92 and is substantially parallel to eliminator 470. Piccolo tube 68 is substantially longer than eliminator 470 so as to extend further down into flash tank 12. Holes 72 of piccolo tube 68 are positioned vertically lower than holes 90 of eliminator 470. Piccolo tube 68 is connected to inlet 462 (which extends through fitting 92), and eliminator 70 is connected to vapor outlet 464 (which also extends through fitting 92). Fitting 92 has fitting interface 94 for connecting fitting 92 to flash tank housing 56 (shown in FIGS. 2A and 2B). In operation, eliminator 470 functions similarly to eliminator 70, except that liquid refrigerant adheres to cylindrical surface 96 of eliminator 470 instead of adhering to blades 74 (shown in FIGS. 5A and 5B) of eliminator 70.

Thus, the various embodiments of eliminators 70, 170, 270, 370, and 470 provide effective and reliable mechanisms for separating liquid refrigerant from vapor refrigerant in flash tanks 12, 112, and 212. This allows for a reduction in the amount of liquid refrigerant supplied to economizer port 40 of compressor 16, thus increasing efficiency and reducing power consumption of compressor 16.

While the invention has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed, but that the invention will include all embodiments falling within the scope of the appended claims. For example, flash tank 12 can be part of a vapor compression system having different components than those illustrated in FIG. 1, such as additional sensors, valves, and passages. 

1. A flash tank for use in a vapor compression system, the flash tank comprising: a flash tank housing; an inlet; a vapor outlet; a liquid outlet; and an eliminator fluidically positioned between the inlet and the vapor outlet, wherein the eliminator comprises a plurality of blades.
 2. The flash tank of claim 1, and further comprising: a condenser fluidically connected to the inlet; a compressor fluidically connected to the vapor outlet; and an evaporator fluidically connected to the liquid outlet.
 3. The flash tank of claim 2, wherein the compressor is fluidically connected to the flash tank via a first passage, fluidically connected to the evaporator via a second passage, and connected to the condenser via a third passage.
 4. The flash tank of claim 1, and further comprising: a piccolo tube connected to the inlet.
 5. The flash tank of claim 1, wherein the flash tank housing has a top and a bottom, wherein the inlet and the vapor outlet are each positioned at the top, and wherein the liquid outlet is positioned at the bottom.
 6. The flash tank of claim 5, wherein the inlet and the liquid outlet are positioned on a first side of the eliminator and the vapor outlet is positioned on a second side of the eliminator.
 7. The flash tank of claim 1, wherein the plurality of blades are substantially vertically aligned between a top support and a bottom support.
 8. The flash tank of claim 1, wherein each of the plurality of blades has at least one bend such that a flow path between the blades has at least one turn.
 9. The flash tank of claim 1, wherein each of the plurality of blades has at least two bends such that a flow path between the blades has at least two turns.
 10. The flash tank of claim 1, wherein the plurality of blades are spaced such that there is no straight line flow path from the inlet to the vapor outlet.
 11. The flash tank of claim 1, wherein the plurality of blades are arranged in a single linear row.
 12. The flash tank of claim 1, wherein the plurality of blades are arranged in at least a first linear row and a second linear angled with respect to the first linear row.
 13. A flash tank for use in a vapor compression system, the flash tank comprising: a flash tank housing; an inlet; a vapor outlet; a liquid outlet; and an eliminator fluidically positioned between the inlet and the vapor outlet, wherein the eliminator comprises a first piccolo tube connected to the vapor outlet.
 14. The flash tank of claim 13, and further comprising: a second piccolo tube connected to the inlet.
 15. The flash tank of claim 14, wherein the flash tank housing has a top and a bottom, wherein the first and second piccolo tubes are each positioned at the top, and wherein the liquid outlet is positioned at the bottom.
 16. The flash tank of claim 14, and further comprising: a fitting rigidly connected to the first and second piccolo tubes, wherein the inlet is a fitting inlet, wherein the vapor outlet is a fitting outlet, and wherein the fitting has a fitting interface for connecting to the flash tank housing.
 17. A method for operating a vapor compression system, the method comprising: flowing refrigerant from a condenser to a flash tank; separating liquid refrigerant from vapor refrigerant via an eliminator that comprises a plurality of blades; flowing vapor refrigerant from the eliminator through a vapor outlet, to a compressor; and flowing liquid refrigerant from the eliminator, through a liquid outlet, to an evaporator.
 18. The method of claim 17, and further comprising: flowing refrigerant from the evaporator to the compressor; and flowing refrigerant from the compressor to the condenser.
 19. The method of claim 17, wherein the liquid refrigerant adheres to the plurality of blades as it passes through channels between the plurality of blades and subsequently flows down the plurality of blades to collect at a bottom of the flash tank.
 20. The method of claim 17, and further comprising: cooling the refrigerant in the condenser via coolant of an aircraft power electronics cooling system; and cooling coolant of an aircraft integrated cooling system via refrigerant in the evaporator. 